This invention relates to a support for photographic photosensitive materials and a process for producing the same, and more particularly, relates to a support for photographic photosensitive materials and a process for producing the same wherein magnetic recording characteristics and/or separability are improved.
Recently, as disclosed in International Publication Nos. WO 90/04205, WO 90/04212 of PCT applications, etc., silver halide photographic photosensitive material (hereinafter simply referred to as photosensitive material) has been provided with a magnetic recording layer. Photographic conditions, such as photographed date, weather and contraction/enlargement ratio, developing and printing conditions, such as the number of reprints, zooming portion and messages can be inputted into the photosensitive material by inputting magnetic recording signals into the magnetic recording layer in a camera or a processing laboratory. Besides, output to image apparatuses such as television and video tape recorder has been possible.
It is also known to a photosensitive material provided with a magnetic recording layer as to automation in manufacturing or finishing processes of the photosensitive material. Yet example, Japanese Patent KOKAI No. 59-203670 discloses a method of inputting photographic emulsion coating conditions into a transparent magnetic recording layer provided into a support of a photographic material and conducting the attachment, detachment or the like of a coater head automatically by reading the coating conditions in a photographic emulsion coating process. Japanese Patent KOKAI No. 60-45248 discloses a method of adding a transparent magnetic recording layer to a COVET sheet and a photosensitive sheet of a mona-sheet type instant photographic photosensitive material and automating to make a suitable combination of the cover sheet with the photosensitive sheet in a collating process. An example of the support for photographic photosensitive materials provided with the magnetic recording layer in, as shown in FIG. 4, composed of a cellulose ester layer 30 onto which a magnetic recording layer 10 is coated.
As the method of adding a magnetic recording layer to a photosensitive material, it is known a method of forming a transparent magnetic recording layer over the whole surface of the photosensitive material (hereinafter referred to as whole surface coating method) which is disclosed in Japanese Patent KOKAI Nos. 50-16161 and 53-10960, Japanese Patent KOKOKU No. 57-6576 and U.S. Pat. No. 3,782,947 and a method of forming a stripe-formed magnetic recording layer on the outside of photographing portions (hereinafter referred to as stripe coating method) which is disclosed in Japanese Patent KOKAI Nos. 50-138037 and 49-42343.
The whole surface laminating method is simpler than the stripe laminating method in the laminating process. However, since the magnetic recording layer is also formed in photographing portions, it induces adverse affects, such as decrease of photosensitivity due to The absorption by the magnetic recording material and degradation of photographic properties by haze. Accordingly, in order to inhibit these adverse affects, it is necessary to render the content of the magnetic recording material as small as possible. However, when The content of the magnetic recording material is reduced, magnetic output properties are degraded.
On the other hand, in the stripe laminating method, since the magnetic recording layer is provided on the outside of photographing portions, there is only a small space for placing the magnetic recording layer because perforations are formed on both outsides of the photographing portion according to the present format of 135 type photographic film. Thereupon, the aforementioned PCT applications propose to form perforations on one side alone, but, even in this case, the space capable of placing the magnetic recording layer is still small. In order to impart a maxiumum record density to the very narrow space, it is necessary to form a magnetic recording layer uniform in the width direction. This is particularly necessary in the case that a homogeneous multichannel head is used to obtain an input/output capacity without dispersion through each head with utilizing the magnetic recording layer from one end to the other in the width direction. The stripe formed magnetic recording layer is usually formed by coating, and there are problems that the thickness of the stripe layer varies at both end portions, that it is difficult to form in rectangle to set the width and the thickness independently and that the coating width is broadened. As a results, a uniform input/output capacity cannot be obtained in the case of using a multichannel head. This matter is caused not only by the difference in the amount of the magnetic recording material in the track of each head but also by the influence of space loss due to the formation of gap between the head and the magnetic recording layer. Particularly, the space loss sharply increases by increasing magnetic record density.
Besides, when a film with a stripe coating is wound into a big roll or in a film cartridges problems occur, such as adhesion of the stripe layer to the emulsion layer, weaving or loosening or collapse of the corner of the stripe layer.
Incidentally, in view of global environment, i.e. to reduce wastes as little as possible, and moreover, in view of the reduction in the manufacturing cost of photosensitive materials, the importance of the utilization of the photosensitive materials as regenerated raw materials has been increasing remarkably. Examples of the photosensitive materials are cut wastes produced by edge trim in the support production process and cut wastes produced by perforation in a finishing process after coating photographic emulsion. In the case of the wastes coated with photographic emulsion, emulsion layer is separated from support, and useful materials such as silver halide are separated therefrom. They are purified and then used again. It is common that the support is also purified and used again as a raw material.
However, it is very difficult to recycle the photosensitive materials containing a magnetic recording layer. That is, in the case of the magnetic recording layers laminated by coating disclosed in Japanese Patent KOKAI Nos. 50-16161 and 60-45248, since they are firmly adhered to cellulose acetate layer, it is not easy to separate the magnetic recording layer from the cellulose acetate layer. Furthermore, in the case of the magnetic recording layer formed by co-casting as disclosed in Japanese Patent KOKAI No. 57-6576, since it is strongly joined to the cellulose acetate layer which is the main body of the support, it is not easy to separate the magnetic recording layer from the cellulose acetate layer.
As mentioned above, conventional supports for photosensitive materials have a problem that it is not easy to separate the magnetic recording layer from the cellulose acetate layer, irrespective of providing the magnetic recording layer by coating or co-casting, and regeneration of the support portion is difficult. This matter also induces a problem of increasing wastes and of increasing manufacturing cost of the photosensitive material.